1. Field of the Invention
This invention relates generally to methods and apparatus for conserving fuel in, and extending the operating life of, internal combustion engines and more particularly, but not by way of limitation, to methods and apparatus for selectively deactivating one or more cylinders of a multi-cylinder internal combustion engine in response to the torque requirements on said engine thereby reducing the fuel consumption of the engine.
2. Description of the Prior Art (Prior Art Statement)
The following statement is intended to be a Prior Art Statement in compliance with the guidance and requirements of 37 CFR Sections 1.56, 1.97 and 1.98 and with Section 609 of the Manual of Patent Examining Procedure.
U.S. Pat. No. 2,078,178 to Johnson shows a device where fuel is bypassed from the combustion chamber concurrent with a deactivation of the spark plug in that chamber. It will be noted, however, that the Johnson device is very dissimilar from the present invention, the principle dissimilarity being that the fuel bypass and ignition deactivation of the Johnson apparatus is not automatically provided in response to engine speed, engine torque or any other engine operating parameter. The fuel bypass and ignition deactivation of Johnson is provided by manual means only. That is, the valve 22 providing for fuel bypass is activated manually by turning the thumb screw 23 thereby moving the valve 22 to an open or closed position. When the valve 22 is moved to an open position, the extension 24 is concurrently moved into electrically grounding contact with the conductor 25 which is attached to the spark plug 15 thereby grounding out the plug and preventing sparking of the same. Furthermore, the Johnson device does not include any means by which fuel bypass can be accomplished in a conventional engine through an arrangement similar to the "spark valve" of the present invention.
U.S. Pat. No. 2,544,463 to Mallory shows a system for cutting off the fuel supply to an engine in conjunction with cutting off the electrical ignition to the engine.
A multitude of systems are provided in the prior art for controlling the ignition of an engine in response to engine speed. An example of such systems is U.S. Pat. No. 3,022,777 to McCloy. McCloy describes an internal combustion engine speed governing means which includes a normally open grounding circuit closable by a speed sensitive switch and communicating electrically with a commutator ring rotatable with the distributor which directs spark inducing circuits to the several cylinders of the engine. A conductor system is provided which connects the ring to such individual spark inducing circuits to cause intermittent interruption of the grounding circuit to that there is excluded therefrom, selected spark inducing circuits. In this way, selective cylinders are rendered temporarily inoperative in response to the engine speed, and the remaining cylinders continue to operate. By this means, the speed of the engine is governed.
Other systems in the prior art similar to McCloy, showing such ignition control are U.S. Pat. Nos. 3,974,805 to Kondo; 3,863,616 to Wood; 3,884,203 to Cliffgard, 3,703,889 to Bodig; 3,158,143 to Heidner, 2,656,827 to Conover; 1,624,975 to Reece; 1,603,744 to Burton; 1,390,376 to Oglesby; and 970,794 to Carlson.
A more refined ignition control system responsive to a combination of engine parameters is that shown in U.S. Pat. No. 4,003,354 to Canup. One of the parameters to which the Canup system is responsive is the torque load on the engine as shown by the torque sensor 48 of Canup.
Several devices have been seen in the prior art which provide means for bypassing unused fuel through a combustion cylinder of an engine. These have principally been found in the diesel engine art where electrical ignition means is not used. For example, U.S. Pat. No. 3,919,986 to Goto shows a system by means of which the output of a diesel engine is controlled by discharging a portion of the combustible mixture from the combustion chamber prior to the ignition thereof. By this means, the output of the Goto device is controlled. A similar concept is shown in U.S. Pat. No. 1,456,337 to Pullin. Additionally, U.S. Pat. No. 1,898,602 to Stamsvik shows a system wherein the flow of fuel to certain cylinders of a multi-cylindered engine is cut off at low engine speeds.
It is seen therefore that none of the apparatus of the prior art include a system wherein the explosive charge of selected cylinders is bypassed through the cylinder and returned to the fuel supply system, automatically in response to variable engine parameters.